Also note that this genus name has frequently been misspelled as "Anastoma" Anostoma, common name the up-mouth snails, is a genus of tropical air-breathing land snails, terrestrial pulmonate gastropod mollusks in the family Odontostomidae.

In 1901, the American malacologist Henry Augustus Pilsbry[3] commented that the adult shell of Anostoma is "so bizarre that in the total absence of information upon its life history, no useful theory can be formulated to account for its peculiarities."

The prominent feature of an upturned aperture (causing the adult snail to carry the shell spire down) is reflected in its scientific name Anostoma: ano, means up, or backwards, and stoma means mouth, from the Greek.

[3] In this genus, the adult snails carry the shell completely upside down, with the umbilicus uppermost, and the spire facing downwards.

[3] Thomas Wyatt (1838)[5] wrote about Anostoma: "An extraordinary shell, sometimes called the antique lamp from its form.

The shell of Anostoma is heliciform, biconvex, solid, the axis hollow, but imperforate in the adult stage.

[3] The semicircular aperture is turned upward, obstructed by numerous lamellae and folds.